﻿using System;

class Program
{
    static void Main()
    {
        try
        {
            int a = int.Parse(Console.ReadLine());
            if (a < 0)
            {
                throw new Exception("Invalid number");
            }
            Console.WriteLine(Math.Sqrt(a));

        }
        catch (Exception)
        {

            Console.WriteLine("Invalid number");
        }
        finally
        {
            Console.WriteLine("Good bye");
        }
    }
}